I recently received a pair of 8D gel deep cycle batteries from someone who changed to AGM. I have been told that my stock 35 amp Yanmar alternator may put out too high a voltage and harm the batteries. Do I need to worry about this? Should I get an external regulator to turn down the voltage output? I generally sail 2-3 days at a time on the weekends. The boat will plugged in to charge during the week with a smart charger.
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Dakota Jim Russell
Gel and Acid Charging Differs
Someone with more intelligence will a better answer . . . but the two types of batteries do have different charging needs. I believe that this will affect your alternator as well as your battery charger.
Someone with more intelligence will a better answer . . . but the two types of batteries do have different charging needs. I believe that this will affect your alternator as well as your battery charger.
Don't think it will be any problem!
Chuck: I have a 1985 H'31. I ran gels for over 10 years without any problem. I did not even have the propper AC charger and they lasted that long. I had an old Pro-Mariner unit for the entire 10 years. If you have a 3 stage smart charger when you are not there, you should be OKAY. You need to set it to the GEL setting. If you don't have one of these chargers you may want to get one anyway. They are good for GEL, AGM and flooded batteries.
Chuck: I have a 1985 H'31. I ran gels for over 10 years without any problem. I did not even have the propper AC charger and they lasted that long. I had an old Pro-Mariner unit for the entire 10 years. If you have a 3 stage smart charger when you are not there, you should be OKAY. You need to set it to the GEL setting. If you don't have one of these chargers you may want to get one anyway. They are good for GEL, AGM and flooded batteries.
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Ray Bowles
I just changed out a gel battery and the
research I did before installing a new gel battery was very strong about recommending the use of a 3 step smart charger. Gel batterys have much different requirements than acid batteries according to the info in the West Marine catolog. Ray
research I did before installing a new gel battery was very strong about recommending the use of a 3 step smart charger. Gel batterys have much different requirements than acid batteries according to the info in the West Marine catolog. Ray
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Russell Egge
With 2-8D's will you need a charge?
You state that you sail for 2-3 days at a time, and the batteries will be charged up before you leave for your trip, your refrid should be cold too. At that rate will you need to recharge? Can you disconnect these batteries from the alternator? If you discharge 2 8-D in 2-3 days you may think about a bigger charger. RREgge S/V Allie Kat
You state that you sail for 2-3 days at a time, and the batteries will be charged up before you leave for your trip, your refrid should be cold too. At that rate will you need to recharge? Can you disconnect these batteries from the alternator? If you discharge 2 8-D in 2-3 days you may think about a bigger charger. RREgge S/V Allie Kat
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Ed Schenck
No details, but. . . .
I did do the research. Just can't remember the numbers. From my Yanmar maintenance manual I studied the output curves for the 35Amp Hitachi alternator. I concluded there was no way that alternator could overcharge my Gel batteries. I'll be starting my fourth season with those batteries(3). I do have my charger(Heart Freedom 20) set for Gels of course. And I leave it on the winter setting.
I did do the research. Just can't remember the numbers. From my Yanmar maintenance manual I studied the output curves for the 35Amp Hitachi alternator. I concluded there was no way that alternator could overcharge my Gel batteries. I'll be starting my fourth season with those batteries(3). I do have my charger(Heart Freedom 20) set for Gels of course. And I leave it on the winter setting.
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Carl and Juliana Dupre
Bigger Alternator
Hi, Chuck! That's a LOT of battery! Gel batteries are voltage-sensitive; much easier to accidently fry than acids. Gels and AGM's are common enough now so that internal regulators may be set so as not to fry them, but a 3-stage external smart regulator is certainly the safe way to go. To us the real issue is the alternator. If you have the electrical loads to suck those 8D's down, we will leave it to you to calculate how long it will take to recharge them using the stock 35 amp alternator. For all practical purposes you might just have yourself a power boat. We would suggest that you consider getting an upgrade to at least a 100 amp alternator, possibly even more than that if you have the loads to really use those 8D's. That would settle your regulator question; most (all?) of the high output alternators require an external regulator. Good luck! Carl and Jule s/v 'Syzygy'
Hi, Chuck! That's a LOT of battery! Gel batteries are voltage-sensitive; much easier to accidently fry than acids. Gels and AGM's are common enough now so that internal regulators may be set so as not to fry them, but a 3-stage external smart regulator is certainly the safe way to go. To us the real issue is the alternator. If you have the electrical loads to suck those 8D's down, we will leave it to you to calculate how long it will take to recharge them using the stock 35 amp alternator. For all practical purposes you might just have yourself a power boat. We would suggest that you consider getting an upgrade to at least a 100 amp alternator, possibly even more than that if you have the loads to really use those 8D's. That would settle your regulator question; most (all?) of the high output alternators require an external regulator. Good luck! Carl and Jule s/v 'Syzygy'
New alternator!
Chuck: If you get one of the 100 or 125 amp alternators from a place like Marathon Marine (http://www.yanmardiesel.com/alternator.html), you should tell them that you have Gel Cells. They will set the regulator for you. If you keep the little 35 amp unit, I doubt that you are going to need to worry.
Chuck: If you get one of the 100 or 125 amp alternators from a place like Marathon Marine (http://www.yanmardiesel.com/alternator.html), you should tell them that you have Gel Cells. They will set the regulator for you. If you keep the little 35 amp unit, I doubt that you are going to need to worry.
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Chuck
More info
I do not currently have anything that requires the 2 8D batteries. They were free. I like the idea of using both to balance the weight port and starboard. With all that weight below the waterline, hopefully the boat will stiffen up a little too. I was planning on having a house bank with a pair of 6 volt golf cart batteries, till these came along. I realize that the 35 amp alternator will take a while to charge these batteries. My concern is, will the Voltage that the alternator puts out be too high for the gel cells? I may not even run the batteries down far enough for the alternator to sense a need to charge.
I do not currently have anything that requires the 2 8D batteries. They were free. I like the idea of using both to balance the weight port and starboard. With all that weight below the waterline, hopefully the boat will stiffen up a little too. I was planning on having a house bank with a pair of 6 volt golf cart batteries, till these came along. I realize that the 35 amp alternator will take a while to charge these batteries. My concern is, will the Voltage that the alternator puts out be too high for the gel cells? I may not even run the batteries down far enough for the alternator to sense a need to charge.
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Carl and Juliana Dupre
External Regulator Still Smart
Hi, again, Chuck. Did a quick check on the West Marine website, and found the following: -2 8D gel cells: $918 -2 golf cart batteries: $200 (small ones) -Balmar ARS IV 3-stage "smart" external regulator: $200 However they came to you, you now have over $900 worth of gel cell batteries. You were prepared to spend at least $200 on a pair of golf cart batteries. Why not spend that same $200 to protect those gorgeous (yes, we are jealous!)8D's and their $900 value? As Steve said, you might do just fine with the current internal regulator. Then again,......... Bottom line: No, you probably don't NEED an external regulator, but it still might be smart. Carl and Jule
Hi, again, Chuck. Did a quick check on the West Marine website, and found the following: -2 8D gel cells: $918 -2 golf cart batteries: $200 (small ones) -Balmar ARS IV 3-stage "smart" external regulator: $200 However they came to you, you now have over $900 worth of gel cell batteries. You were prepared to spend at least $200 on a pair of golf cart batteries. Why not spend that same $200 to protect those gorgeous (yes, we are jealous!)8D's and their $900 value? As Steve said, you might do just fine with the current internal regulator. Then again,......... Bottom line: No, you probably don't NEED an external regulator, but it still might be smart. Carl and Jule
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